1. Technical Field of the Invention
This invention relates to a communication control apparatus that controls communication between equipment which is selectively connectable to a first network and an external station wherein the external station is connected to the equipment through a second network. The equipment is preferably a printing apparatus which is used in conjunction with the communication control apparatus in a printing system to increase data security and prevent unauthorized access to data through the printer.
2. Description of Related Art
In conventional systems, it is known to perform a so-called remote maintenance of a copying apparatus. In these systems, an external service station calls up the copying apparatus via a modem that is installed with the copier and collects operation related data directly from the copier. Such operation related data may include, for example, the number of copies made since the last service, status of different parts, jam occurrence, toner replenishment etc. In this way, it is possible for the service station to provide accurate servicing of the copying apparatus in a timely manner and also enables the service station to check and track the frequency of equipment errors.
With reference to FIG. 1, a conventional infrastructure commonly used in modern offices will be explained. Printer 2 is connected to an internal network 1. The internal network 1 typically supplies the printer 2 with printer data from individual work stations. To service the printer 2, the service station 5 (normally an external firm) needs to receive access to status data from the printer 2 via a public telephone line 4. For this purpose, a conventional communication control apparatus 3 including a standard telephone modem is connected to the printer 2. In this way, the external service station 5 may call up the printer 2 via the public telephone line 4 and read out the status data automatically.
A data security problem is created by this conventional infrastructure. The source of this problem is that not only may the authorized external service station 5 call the printer 2 via the telephone line 4, but also an unauthorized person may access the printer 2 in this way. In other words, the printer 2 can serve as a back door which can be opened by unauthorized persons to access confidential data. This results in the customer being anxious that an unauthorized person could get access, via the printer 2, to confidential data on the internal network 1. Thus, the customer may refuse to allow the service station to install such modem because of the data security risk that such an installation presents.
Another example of such remote maintenance is disclosed in document EP-A-0 509 528. This document discloses a communication control apparatus connected to a copier in order to control the communication with the remote host computer. In order to not disturb an ongoing copy operation, the communication is controlled so that a data transfer via modem can only take place when the copier is not copying a document. This remote maintenance system is also susceptible to infiltration by an unauthorized person and poses a data security risk as discussed above.
To address this data security risk, two main solutions have been proposed in the prior art: the provision of a password access control as disclosed in document EP-A-0 513 549 and a call-back technique as disclosed in JP-A-02 237356.
The call-back technique has disadvantages. The call-back technique involves the service station calling-up the copier and the copier then calling-back the service station from a list of authorized, internally stored phone numbers. If the service station relocates or otherwise changes phone numbers, then the internal authorized phone number list must be updated. The customer may also experience increased phone bills due to this call-back procedure--especially if the service station phone number is long distance.
Because a password can be compromised or cracked, password protection for external access is not sufficient to ensure data security. Furthermore, passwords are inconvenient because they must be memorized and their confidentiality protected by such measures as long, complex passwords and frequent changing of the password. If the password is forgotten, the external service station will experience further difficulties.
The proliferation of unscrupulous hackers and industrial espionage heightens the above-described data security risk. Thus, there is a need for a reliable data security measure in this field.